This core is a central morphology facility providing support for the investigators in the program project. This includes light microscopy, transmission electron microscopy, immunofluorescence and immunohistochemistry processing and analysis plus where indicated scanning electron microscopy, morphometric analysis, photographic and graphic illustration services. Based on our previous experience light microscopy, transmission electron microscopy and immunohistochemistry will be the services most heavily utilized by investigators. During this past year, over 1,500 samples were processed for light microscopy analysis and it is anticipated that there will be continue heavy demand for this service by all sections of the program project. For example, in section I, II, III, and IV light microscopy will be routinely used to monitor the intensity of the lung injury in the various models. In addition, in vitro studies of isolated cells and tissue culture monolayers in section I, II, III, and V will utilize this technique. Transmission electron microscopy (TEM) will also be utilized extensively for this program project particularly in sections I,II, and IV for assessment of injury to endothelial and epithelial cells in vivo and sections II, III and V where alterations in granulomas will be assessed by this method. TEM also is used for morphometric analysis of tissue alterations. Scanning electron microscopy (SEM) will be utilized in selected cases primarily to evaluate injury to the alveolar surface of the lung by adherent leukocytes in section I. Frozen section analysis of tissues and cells, particularly immunohistochemistry, is heavily utilized currently by investigators and this will continue in the current proposal. Immunohistochemistry is the primary technique for evaluating adhesion molecule and cytokine upregulation in vivo and in vitro and will be used extensively for this purpose in section I, II, III, and V. Selected immunofluorescence studies will be done in vivo to evaluate immune complex induced injury and the effects on interventional studies and in vitro to assess binding of monocytes to endothelial cells in section V. Morphometric analysis now routinely done to precisely quantify the intensity of lung injury in vivo and the effects of therapeutic interventions by measuring parameters such as granuloma size, leukocyte influx, hemorrhage and injury to parenchymal cells including and epithelial cells. Finally, the core facility routinely offers photographic and graphic services for investigators in the program project including preparations of poster and publication graphics.